Emissive device and electronic apparatus

ABSTRACT

An emissive device includes a substrate; a switching element disposed on a surface of the substrate; an insulating layer covering the switching element; a contact hole disposed in the insulating layer; a first electrode disposed on a surface of the insulating layer and electrically connected to the switching element via the contact hole in the insulating layer; a second electrode disposed at a side opposite the substrate with respect to the first electrode; a luminescent layer disposed between the first electrode and the second electrode; and a light shield disposed at a side from which light from the luminescent layer emerges and having a portion covering the contact hole when viewed in a direction perpendicular to the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese PatentApplications Nos. JP 2005-328491, and JP 2006-088287, filed in theJapanese Patent Office on Nov. 14, 2005, and Mar. 28, 2006,respectively, the entire disclosures of which are hereby incorporated byreference in their entireties.

BACKGROUND

1. Technical Field

The present invention relates to structures of emissive devicesincluding various emissive materials such as organic electroluminescentmaterials.

2. Related Art

Active matrix emissive devices including switching elements, such astransistors, for controlling light emission from luminescent layers havebeen proposed. For example, JP A-2002-318556 discloses such an emissivedevice including the switching element disposed on a surface of asubstrate, an insulating layer covering the switching element, a firstelectrode and a second electrode that are disposed on the surface of theinsulating layer, and the luminescent layer disposed between theelectrodes. The first electrode is electrically connected to theelectrode (a drain electrode or a source electrode) of the switchingelement via a contact hole disposed in the insulating layer.

However, in this structure, external light, such as sunlight and lightfrom a luminaire, passes through the contact hole in the insulatinglayer, reaches the electrode of the switching element, is reflected fromthe surface, and emerges from a viewing side, in some cases. The lightreflected from the surface is referred to as “undesirable reflection”,hereinafter. The undesired reflection has characteristics, such as lightintensity and spectral characteristics, different from those of lightfrom the luminescent layer, thus causing the nonuniformity of thequantity of light, i.e., nonuniformity of luminance, in the plane of theemissive device.

Furthermore, for example, in a structure in which a luminescent layer isformed not only on an insulating layer but also inside a contact hole,light (hereinafter, referred lo as “undesirable light”) is also emittedfrom the portion of the luminescent layer disposed along the innersurface of the contact hole. However, the portion of the luminescentlayer disposed on the surface of the insulating layer has a thicknessdifferent from that of the portion of the luminescent layer disposedinside the contact hole; hence, light emitted from the former portionhas the quantity of light and spectral characteristics different fromthose of the light emitted from the latter portion. Therefore, theundesirable light in the structure can also cause the nonuniformity(unevenness) of the quantity of light in the plane of the emissivedevice.

SUMMARY

As described above, in the structure in which the switching element iselectrically connected to the first electrode via the contact hole inthe insulating layer, the undesirable reflection from the electrodedisposed at the bottom of the contact hole and the undesirable emittedlight from the luminescent layer inside the contact holedisadvantageously cause the nonuniformity of light intensity, i.e.,degrade the evenness of the light emission. An advantage of some aspectsof the invention is to suppress the nonuniformity of the quantity oflight due to the contact hole of the insulating layer.

According to an aspect of the invention, an emissive device includes asubstrate; a switching element disposed on a surface of the substrate(for example, a driving transistor Tdr shown in FIG. 2); an insulatinglayer covering the switching element (for example, an second insulatinglayer 42 shown in FIG. 3); a contact hole (for example, a contact holeCH shown in FIGS. 2 and 3) disposed in the insulating layer; a firstelectrode disposed on a surface of the insulating layer and electricallyconnected to the switching element via the contact hole in theinsulating layer; a second electrode disposed at a side opposite thesubstrate with respect to the first electrode; a luminescent layerdisposed between the first electrode and the second electrode; and alight shield (for example, a auxiliary lead 70 or a light-shieldinglayer 81 in each embodiment) disposed at a side from which light fromthe luminescent layer emerges and having a portion covering the contacthole when viewed in a direction perpendicular to the substrate.

According to the structure, the light shield overlapping the contacthole when viewed in the direction perpendicular to the substrate isdisposed at a viewing side with respect to the insulating layer, i.e.,the light shield is disposed at the side from which light from theluminescent layer emerges. As a result, external light, such as sunlightand light from a luminaire, is blocked by the light shield and thus doesnot reach the contact hole or the switching element (in particular, theelectrode of the switching element). Even if external light passesthrough the contact hole to reach the switching element, the undesirablereflection from the surface is blocked by the light shield. Furthermore,in a structure in which the luminescent layer is disposed inside thecontact hole (for example, FIGS. 9 to 13), the undesirable light emittedfrom the portion of the luminescent layer disposed along the innersurface of the contact hole is blocked by the light shield. As describedabove, according to an aspect of the invention, since the undesirablereflection and the undesirable light are blocked by the light shield, itis possible to suppress the nonuniformity of the quantity of light dueto the contact hole.

The phrase “the side from which light from the luminescent layer emergeswith respect to the insulating layer” means a side designed in a marinersuch that light emitted from the luminescent layer emerges from theside. For example, in a bottom emission device including the firstelectrode that transmits light, a substrate side with respect to theinsulating layer corresponds to “the side from which light from theluminescent layer emerges”. In a top emission device including thesecond electrode that transmits light, a side opposite to the substratewith respect to the insulating layer corresponds to “the side from whichlight from the luminescent layer emerges”. From the standpoint of theapplication of the emissive device, in the case where the emissivedevice is used as a display, a viewing side with respect to theinsulating layer corresponds to the “the side from which light from theluminescent layer emerges”, i.e., the viewing side corresponds to theside at which an observer that visually identifies an image displayedwith the emissive display is located. In the case where the emissivedevice is used as an exposure device (exposure head) for exposing aphotoreceptor, such as a photosensitive drum, a photoreceptor side withrespect to the insulating layer corresponds to “the side from whichlight from the luminescent layer emerges”.

When the light shield has a higher light reflectivity than the electrodeof the switching element, the nonuniformity of light emission due to thecontact hole is surely eliminated. However, external light reflectedfrom the light shield may have an effect on the uniformity of the lightemission. According to a preferred aspect of the invention, theswitching element further includes an electrode (for example, a drainelectrode 34 shown in FIGS. 2 and 3) extending through the contact holeand having a portion not covered with the insulating layer, the portionbeing in contact with the first electrode, wherein the light shield iscomposed of a material having a lower light reflectivity than theelectrode of the switching element. In this structure, since the lightshield is composed of a material having a lower light reflectivity thanthe electrode of the switching element, the influence of both reflectiondue to the contact hole and reflection due to the light shield iseliminated to improve the uniformity of the light emission.

In the case of the second electrode with high resistance, a voltage dropacross the second electrode may degrade the uniformity of lightemission. In a structure (top emission type) in which the secondelectrode is composed of a high-resistance material, such as indium tinoxide (ITO) or indium zinc oxide (IZO), and a structure in which thesecond electrode extends widely and continuously, the voltage dropacross the second electrode is particularly significant, thus furtherdegrading the nonuniformity of light emission. According to a preferredaspect of the invention, an auxiliary lead composed of a conductivematerial having a lower resistivity than the second electrode andelectrically connected to the second electrode is used as the lightshield. In this structure, the auxiliary lead electrically connected tothe second electrode suppresses the voltage drop, thereby improving thenonuniformity of light emission due to the voltage drop. Embodiments ofthe aspect will be described as a first embodiment (FIGS. 2 and 3), asecond embodiment (FIGS. 5 and 6), a fourth embodiment (FIG. 9), a fifthembodiment (FIG. 10), and a eighth embodiment (FIGS. 14 and 15).

The structure in which the auxiliary lead is also used as the lightshield is exemplified above. Alternatively, in an aspect of theinvention, a structure in which an auxiliary lead separate from thelight shield is disposed may also be used. In the latter structure, theauxiliary lead composed of a material having satisfactory opticaltransparency does not cause a particular problem. However, to meet therequirement that the auxiliary lead has a lower resistivity than thesecond electrode, in many cases, a conductive material is necessarilyselected as the material for the auxiliary lead. In the structure inwhich the auxiliary lead separate from the light shield is disposed, anaperture ratio, i.e., the ratio of an area from which light is actuallyemitted to an area at which pixels are disposed, is disadvantageouslyreduced by an area at which the auxiliary lead is disposed, as comparedwith a structure in which the auxiliary lead is not disposed. Incontrast, as exemplified above, according to the aspect in which theauxiliary lead is also used as the light shield, the aperture ratio isadvantageously increased compared with the structure in which theauxiliary lead separate from the light shield is disposed. The increasedaperture ratio results in a reduction in electrical energy to be fed tothe luminescent layer for emitting light with a predetermined quantityof light from the emissive device. Higher electrical energy promotes thedegradation of characteristics of the luminescent layer (in particular,composed of an organic electroluminescent material). Thus, in the aspectin which the electrical energy fed to the luminescent layer can bereduced, the life of the luminescent layer (time required for values ofcharacteristics, such as the quantity of light and luminous efficiency,to decrease to a predetermined value) can be advantageously prolonged,as compared with the structure in which the aperture ratio is limited tothe auxiliary lead.

In the aspect in which the auxiliary lead is used as the light shield,more preferably, the auxiliary lead completely covers a regionsurrounded by the inner periphery of the contact hole when viewed in thedirection perpendicular to the substrate. According to the aspect, it ispossible to further increase the rate in which the light shield blocksthe undesirable reflection and the undesirable light due to the contacthole. Embodiments of the aspect will be described below as the firstembodiment (FIGS. 2 and 3) and the fourth embodiment (FIG. 9). In theformation of the light shield (auxiliary lead) by a film-formingtechnique, such as evaporation using a mask, when the light shield isformed so as to completely cover the opening of the contact hole, theposition of the light shield is deviated from a designed position due tononuniformity in a production process, i.e., due to the deviation of themask, in some cases. Such a structure in which part of the opening isnot covered with the light shield because of the error also meets therequirement of the aspect that “the light shield completely covers theregion surrounded by the inner periphery of the contact hole”, as longas the light shield is designed to completely cover the opening.

Alternatively, the auxiliary lead may be designed to partially overlapthe region surrounded by the inner periphery of the contact hole (forexample, a region A1 shown in FIGS. 6 and 10) when viewed in thedirection perpendicular to the substrate. In this structure, morepreferably, a light-shielding layer having a portion overlapping aregion not overlapping the auxiliary lead in the region surrounded bythe inner periphery of the contact hole (for example, a region A2 shownin FIGS. 6 and 10) is further disposed. In this structure, theundesirable reflection and the undesirable light that are not blocked bythe auxiliary lead are blocked by the light shielding layer. Thus, inthe same way as in the aspect in which the auxiliary lead completelycovers the opening of the contact hole, it is possible to furtherincrease the rate in which the light shield blocks the undesirablereflection and the undesirable light due to the contact hole.Embodiments of the aspect will be described below as, for example, thesecond embodiment (FIGS. 5 and 6) and the fifth embodiment (FIG. 10).

The structure in which the auxiliary lead is also used as the lightshield is exemplified above. Alternatively, in an aspect of theinvention, a structure in which an auxiliary lead separate from thelight shield is disposed may also be used. In the aspect, if theauxiliary lead has light reflectivity, reflection (external light) fromthe surface of the auxiliary lead may degrade the uniformity of lightemission. Accordingly, in more preferred aspect, the light shieldoverlaps the auxiliary lead when viewed in the direction perpendicularto the substrate. According to the aspect, the light shield also blocksreflection from the surface of the auxiliary lead as well as theundesirable reflection and the undesirable light due to the contacthole; hence, it is possible to maintain the uniformity of lightemission. In other words, even when the auxiliary lead is composed of aconductive material having light reflectivity, the uniformity of lightemission is not impaired. This can advantageously expand the range ofmaterial options for the auxiliary lead. Embodiments of the aspect willbe described below as, for example, the third embodiment (FIGS. 7 and8), a sixth embodiment (FIG. 11), and a seventh embodiment (FIGS. 12 and13).

In the above-described aspects, any shape of the auxiliary lead may beused. In an aspect in which a plurality of element groups (for example,each group including a plurality of luminescent elements being arrangedin each row) each including a plurality of luminescent elements arearranged in a second direction crossing a first direction, theluminescent elements each having the first electrode, the secondelectrode, and the luminescent layer and being arranged in the firstdirection (for example, the X-direction in FIG. 16), for example, eachauxiliary lead is disposed in the space (for example, a space S1 shownin FIG. 16) between a first element group (for example, row i shown inFIG. 16) and a second element group (for example, row (i+1)) adjacent tothe first element group, the auxiliary lead extending in the firstdirection. The auxiliary lead is not disposed in the space (for example,a space S2 shown in FIG. 16) between the second element group and athird element group (for example, row (i+2) shown in FIG. 16) which isadjacent to the second element group and which is disposed at a positionopposite to the first element group with respect to the second elementgroup. In this aspect, since the auxiliary lead is not disposed on thespace between the second element group and the third element group, itis possible to reduce the areas of a region in which the auxiliary leadsare disposed and of a region (marginal region) ensured between theauxiliary lead and the luminescent clement, as compared with a structurein which each of the auxiliary leads is disposed in the space betweenany adjacent element groups. Thus, this structure easily achieves abalance between the improvement of the aperture ratio and a reduction inthe resistance of the auxiliary lead. For example, the aperture ratiocan be increased without a reduction in the line width of the auxiliarylead. Alternatively, the line width of the auxiliary lead can beincreased (a reduction in resistance) without a reduction in apertureratio (area of the luminescent element).

In the above-described structure in which a single auxiliary lead isdisposed with respect to a unit of two or more element groups, in orderto form the auxiliary lead, evaporation is suitably employed with amask. That is, in a process for producing the emissive device, a step offorming the auxiliary lead includes preparing a mask having apredetermined shape; and depositing a material having a lowerresistivity than the second electrode by evaporation with the mask toform the auxiliary lead. The mask prepared in the former step has anopening at a region (for example, a region RA shown in FIG. 18) facingthe space between the first element group and the second element groupadjacent to the first element group and has an unperforated regionfacing the space between the second element group and the third elementgroup which is adjacent to the second element group and which isdisposed at a position opposite to the first element group with respectto the second element group. The mask for use in the step has theunperforated region facing the space between the second element groupand the third element group and thus has higher mechanical strength, ascompared with that of a mask having openings perforated at regions eachfacing a space between any adjacent element groups. Therefore, the errorof the auxiliary lead and the failure of the mask due to the deformationof the mask are suppressed.

According to a preferred aspect of the invention, a space in the contacthole is filled with an insulating portion composed of an insulatingmaterial, and the luminescent layer is not disposed in the contact hole.According to the structure, since the luminescent layer is not presentin the contact hole, the uniformity of light emission is not impaired bythe undesirable light emitted from the portion. Embodiments of theaspect will be described below as, for example, the first embodiment(FIGS. 2 and 3), the second embodiment (FIGS. 5 and 6), and the thirdembodiment (FIGS. 7 and 8). The luminescent layer may be disposed so asto be separated with the insulating portion. Alternatively, theluminescent layer may be continuously disposed so as to cover theinsulating portion (for example, see FIG. 20).

In another aspect of the invention, the light shield extends to apredetermined direction, and the contact hole has a length along thepredetermined direction when viewed in the direction perpendicular tothe substrate. According to the aspect, the area of the contact hole issufficiently ensured; hence, it is possible to reduce the resistance ofa contact region between the first electrode and the switching element.Alternatively, it is possible to increase the reliability of thecontinuity between the first electrode and the switching element.

An emissive device according to an aspect of the invention can be usedas any one of a top-emission-type emissive device and abottom-emission-type emissive device. In the top-emission-type emissivedevice, the second electrode transmits light emitted from theluminescent layer. In the bottom-emission-type emissive device, thefirst electrode transmits light emitted from the luminescent layer. In apreferred aspect of the bottom-emission-type emissive device, theswitching element includes an electrode extending through the contacthole, the electrode having a portion not covered with the insulatinglayer, and the portion being in contact with the first electrode. Thelight shield is composed of a material having a lower light reflectivitythan the electrode of the switching element and is disposed between theelectrode of the switching element and the substrate, the light shieldbeing opposite to the electrode. Also according to the aspect, the lightshield blocks the reflection from the electrode of the switchingelement, thus maintaining the uniformity of light emission. Theembodiment of the bottom-emission-type emissive device will be describedbelow as the eighth embodiment (FIGS. 14 and 15).

In the bottom-emission-type emissive device as exemplified above, astructure in which the auxiliary lead is also used as the light shieldis also used. In the structure, the auxiliary lead is electricallyconnected to the second electrode via the contact hole (for example, acontact hole CH5 shown in FIG. 14) in the insulating layer. Furthermore,the light shield is preferably composed of the same material as that ofa subelement (for example, a gate electrode 242 shown in FIG. 14)constituting the switching element. According to the aspect, theelectrodes of the switching element and the light shield can besimultaneously formed by patterning a single conductive film. Thus, itis possible to simplify a production process and reduce productioncosts, as compared with the case where the light shield is formed by astep different from a step of forming the switching element.

An emissive device according to an aspect of the invention is used inany one of various electronic apparatuses. An exemplary electronicapparatus is an apparatus including the emissive device functioning as adisplay. Examples of the apparatus include personal computers andcellular phones. However, the application of the emissive deviceaccording to an aspect of the invention is not limited to displaying animage. Examples of the application include an exposure device (exposurehead) for forming a latent image on an image carrier, such as aphotosensitive drum, by irradiation of light; a device (backlight) forilluminating a liquid-crystal apparatus, the device being disposed atthe back side of the liquid-crystal apparatus; and an apparatusinstalled in an image scanner or the like and for illuminating a sourcedocument. In this way, the emissive device according to an aspect of theinvention can be applied to any one of various applications.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a circuit diagram showing an electrical structure of anemissive device according to a first embodiment of the invention.

FIG. 2 is a plan view showing the structure of a pixel.

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2.

FIG. 4 is a plan view of an example of the structure of an auxiliarylead.

FIG. 5 is a plan view showing the structure of a pixel according to asecond embodiment of the invention.

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5.

FIG. 7 is a plan view of the structure of a pixel according to a thirdembodiment of the invention.

FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7.

FIG. 9 is a cross-sectional view showing the structure of a pixelaccording to a fourth embodiment of the invention.

FIG. 10 is a cross-sectional view showing the structure of a pixelaccording to a fifth embodiment of the invention.

FIG. 11 is a cross-sectional view showing the structure of a pixelaccording to a sixth embodiment of the invention.

FIG. 12 is a plan view showing the structure of a pixel according to aseventh embodiment of the invention.

FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12.

FIG. 14 is a plan view showing the structure of a pixel according to aneighth embodiment of the invention.

FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14.

FIG. 16 is a plan view showing the arrangement of pixels according to aninth embodiment of the invention.

FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. 16.

FIG. 18 is a cross-sectional view illustrating a step of formingauxiliary leads.

FIG. 19 is a plan view showing the arrangement of the pixels accordingto another aspect of the ninth embodiment.

FIG. 20 is a cross-sectional view showing the structure of a pixelaccording to the modification of each embodiment.

FIG. 21 is a perspective view showing an example of an electronicapparatus according to an aspect of the invention.

FIG. 22 is a perspective view showing an example of an electronicapparatus according to an aspect of the invention.

FIG. 23 is a perspective view showing an example of an electronicapparatus according to an aspect of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS A: First Embodiment

FIG. 1 is a diagram showing the electrical structure of an emissivedevice according to a first embodiment of the invention. The emissivedevice D is incorporated in any one of various electronic apparatusesand serves as a display for displaying an image. As shown in FIG. 1, theemissive device D includes a plurality of selection lines 11 eachextending in the X-direction and a plurality of signal lines 13 eachextending in the Y-direction perpendicular to the X-direction. Pixels Pare disposed at intersections between the selection lines 11 and thesignal lines 13. Therefore, the pixels P are arranged in the x andY-directions, i.e., the pixels P are arrayed in a matrix in apredetermined region (hereinafter, referred to as a “luminescentregion”).

Each pixel P includes a luminescent element E that luminesces when acurrent is fed thereto, a driving transistor Tdr for controlling thecurrent fed to the luminescent element E, and a section transistor Tsl.The luminescent element E includes a luminescent layer 66 composed of anorganic electroluminescent material, a first electrode 61, and a secondelectrode 62, the luminescent layer 66 being disposed between the firstelectrode 61 and the second electrode 62. The luminescent layer 66 emitslight with luminance (quantity of light) in response to a current thatflows from the first electrode 61 to the second electrode 62.

The driving transistor Tdr is a switching element for controlling acurrent feed to the luminescent element E. A source electrode isconnected to a power line 15. A higher power-supply potential Vdd isapplied to the Dower line 15. A capacitor C for maintaining thepotential of the gate electrode is disposed between a gate electrode andthe source electrode of the driving transistor Tdr. The drain electrodeof the driving transistor Tdr is connected to the first electrode 61 ofthe luminescent element E. A lower power-supply potential Gnd is appliedto the second electrode 62 of the luminescent element E via an auxiliarylead 70. The effect and the specific shape of the auxiliary lead 70 willbe described below.

The selection transistors Tsl are each disposed between the gateelectrode of the driving transistor Tdr and the signal line 13 andserves as a switching element for controlling the electrical connectionbetween the gate electrode of the driving transistor Tdr and the signalline 13. The gate electrode of each selection transistor Tsl isconnected to the selection line 11. In this embodiment, a structureincluding a p-channel driving transistor Tdr and an n-channel selectiontransistor Tsl is exemplified. However, the conductivity type of eachtransistor may be desirably changed.

A selection signal fed to the selection lines 11 shifts to an activelevel to bring the selection transistor Tsl into an ON state. As aresult, a data potential Vdata in response to a specified gray scale ofthe pixel P is applied from the signal line 13 to the gate electrode ofthe driving transistor Tdr via the selection transistor Tsl. At thistime, charge in response to the data potential Vdata is accumulated inthe capacitor C. Thus, even when the selection lines 11 shifts to anonactive level to bring the selection transistor Tsl into an OFF state,the potential applied to the gate electrode of the driving transistorTdr is maintained at the data potential Vdata. A current in response tothe potential applied to the gate electrode of the driving transistorTdr, i.e., the current in response to the data potential Vdata, is fedto the luminescent element E. As a result, the luminescent element Eilluminates at a luminance level (the quantity of light) in response tothe data potential Vdata.

FIG. 2 is a plan view showing a specific structure of a single pixel P.FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2.Although FIG. 2 is a plan view, in order to easily understand elements,the same elements as those shown in FIG. 3 are hatched using the samehatch patterns as those shown in FIG. 3. The same is true in plan views(FIGS. 5, 7, 12, and 14) according to the following embodiments. In FIG.2, for the sake of convenience, the luminescent layer 66 and the secondelectrode 62 shown in FIG. 1 are not shown.

As shown in FIG. 3, the elements, such as the driving transistor Tdr andthe luminescent element E, shown in FIG. 1 are disposed on a surface ofa substrate 10. The substrate 10 is a flat member composed of aninsulating material, such as glass or plastic, and having asubstantially rectangular shape. The elements of the pixel P may bedisposed on an underlying insulating film, such as a film composed ofsilicon oxide or silicon nitride, covering the substrate 10.Hereinafter, a side in which the driving transistor Tdr and theluminescent element E are disposed with respect to the substrate 10,i.e., the upper side in FIG. 3, is referred to as a “viewing side”. Thatis, the term “viewing side” means the side at which an observer thatvisually identifies an image displayed with the emissive display D islocated.

As shown in FIGS. 2 and 3, the driving transistor Tdr includes asemiconductor layer 31 disposed on a surface of the substrate 10, a gateinsulating layer 40 disposed on the entire surface of the substrate 10and covering the semiconductor layer 31, a gate electrode 242 disposedon the semiconductor layer 31 provided with the gate insulating layer 40therebetween, a source electrode 33, and a drain electrode 34. Thesemiconductor layer 31 is composed of a semiconductor material such assilicon and is a film having a substantially rectangular shape.

As shown in FIG. 2, an intermediate conductor 24 is disposed on the gateinsulating layer 40. The intermediate conductor 24 has a portionextending in the X-direction, the portion being in contact with thesemiconductor layer 31. The contact area is the gate electrode 242. Asshown in FIG. 3, the semiconductor layer 31 includes a channel region 31c opposite the gate electrode 242 provided with the gate insulatinglayer 40 therebetween, a source region 31 s, and a drain region 31 d,the channel region 31 c being disposed between the source region 31 sand the drain region 31 d.

As shown in FIG. 3, the entire surface of the substrate 10 having thesemiconductor layer 31 and the gate electrode 242 (intermediateconductor 243 is covered with a first insulating layer 41. The sourceelectrode 33 and the drain electrode 34 are disposed on the surface ofthe first insulating layer 41. As shown in FIG. 2, the source electrode33 is a portion of the power line 15 extending the X-direction. Thesource electrode 33 is electrically connected to the source region 31 sof the semiconductor layer 31 via a contact hole CH1 a passing throughthe first insulating layer 41 and the gate insulating layer 40.

The drain electrode 34 has a unitary structure of a first portion 341and a second portion 342. The first portion 341 is electricallyconnected to the drain region 31 d of the semiconductor layer 31 via acontact hole CH1 b passing through the first insulating layer 41 and thegate insulating layer 40. The second portion 342 is a portion extendingin the X-direction, as shown in FIG. 25.

As shown in FIG. 2, the intermediate conductor 24 includes an electrodeportion 244 covered with the power line 15 and an interconnectionportion 246 extending from the gate electrode 242 toward the Y-directionand crossing the power line 15. The electrode portion 244 is oppositethe power line 15 provided with the first insulating layer 41therebetween to form the capacitor C shown in FIG. 1.

As shown in FIG. 2, the selection transistor Tsl includes asemiconductor layer 51 disposed on the surface of the substrate 10, agate electrode 112 opposite the channel region of the semiconductorlayer 51 provided with the gate insulating layer 40 therebetween, adrain electrode 53 disposed on the surface of the first insulating layer41 covering the gate electrode 112, and a source electrode 54. The gateelectrode 112 is a portion branched off in the Y-direction from theselection lines 11 extending in the X-direction, the portion coveringthe semiconductor layer 51. The selection lines 11 and the intermediateconductor 24 are simultaneously formed by patterning a common conductivefilm. Similarly, the drain electrode 53, the source electrode 54, thesource electrode 33 (power line 15) and the drain electrode 34 of thedriving transistor Tdr are simultaneously formed by patterning a singleconductive film.

The drain electrode 53 is electrically connected to the drain region ofthe semiconductor layer 51 via a contact hole CH2 b passing through thefirst insulating layer 41 and the gate insulating layer 40. Similarly,the source electrode 54 is electrically connected to the source regionof the semiconductor layer 51 via a contact hole CH2 a. The sourceelectrode 54 is electrically connected to the interconnection portion246 of the intermediate conductor 24 via a contact hole CH3 passingthrough the first insulating layer 41. As a result, the source electrode54 of the selection transistor Tsl is electrically connected to the gateelectrode 242 of the driving transistor Tdr.

As shown in FIG. 2, the signal lines 13 shown in FIG. 1 includes anintersection portion 131 disposed under the power line 15 and extendingin the Y-direction to cross the power line 15; and an interconnectionportion 132 disposed between the power lines 15 and extending in theY-direction. The intersection portion 131 is formed of the conductivefilm common to the selection lines 11 and the intermediate conductor 24.The interconnection portion 132 is formed of the conductive film commonto the source electrode 33 and the drain electrode 34 of the drivingtransistor Tdr. The end 13 a of the interconnection portion 132 iselectrically connected to the intersection portion 131 via a contacthole CH4 a in the first insulating layer 41. Similarly, the end 13 b ofthe interconnection portion 132 is electrically connected to theintersection portion 131 via a contact hole CH4 b in the firstinsulating layer 41. As described above, the signal lines 13 have theelectrical connection of the intersection portions 131 and theinterconnection portions 132. The drain electrode 53 of the selectiontransistor Tsl is a portion of the interconnection portion 132, theportion overlapping the semiconductor layer 51.

As shown in FIG. 3, the entire surface of the first insulating layer 41having the power line 15 and the drain electrode 34 is covered with asecond insulating layer 42. The first insulating layer 41 and the secondinsulating layer 42 are composed of an insulating material, such assilicon oxide or silicon nitride. As shown in FIGS. 2 and 3, a contacthole CH is formed at a portion where the second insulating layer 42overlaps the second portion 342 of the drain electrode 34 when viewed ina direction perpendicular to the substrate 10, the contact hole CHpassing through the second insulating layer 42 in the thicknessdirection. Thus, the second portion 342 is not covered with the secondinsulating layer 42 but exposed at the contact hole CH. As shown in FIG.2, when viewed in the direction perpendicular to the substrate 10, thecontact hole CH has a substantially rectangular shape and has a lengthalong the X-direction.

Reflective layers 44 having substantially rectangular shapes are eachdisposed on the surface of the second insulating layer 42 for everypixel P, the reflective layers 44 being separated from each other. Thereflective layer 44 is composed of a material having light reflectivity,for example, an aluminum alloy, a silver alloy, or an alloy mainlycontaining aluminum or silver. The reflective layer 44 reflects lightemitted from the luminescent layer 66 toward the substrate 10 to theviewing side (the upper side of FIG. 3). Furthermore, first electrodes61 (see FIG. 1) functioning as anodes of the luminescent elements E areeach disposed on the surface of the second insulating layer 42 for everypixel P, the first electrodes 61 being separated from each other. Eachfirst electrode 61 is a substantially rectangular electrode covering thereflective layer 44. The first electrodes 61 are each composed of anoptically transparent conductive material, such as indium tin oxide(ITO) or indium zinc oxide (IZO). As shown in FIGS. 2 and 3, the firstelectrode 61 is disposed in the contact hole CH in the second insulatinglayer 42 and is in contact with the drain electrode 34 (second portion342) of the driving transistor Tdr, thereby electrically connecting thefirst electrode 61 and the driving transistor Tdr.

The first electrode 61 is formed by any one of various film-formingtechniques, such as sputtering and vacuum evaporation, so as to have asufficiently thin thickness with respect to the external dimension ofthe contact hole CH. Thus, as shown in FIG. 3, the first electrode 61has a recess 611 (depression) in response to the film thickness of thesecond insulating layer 42 and the external dimension of the contacthole CH. That is, the portion of the first electrode 61 being in contactwith the drain electrode 34 corresponds to the bottom of the recess 611.The portion of the first electrode 61 covering the inner periphery ofthe first electrode 61 corresponds to the side faces of the recess 611.

As shown in FIG. 3, an insulating portion 64 is disposed inside therecess 61 i.e., the insulating portion 64 is disposed in a space insidethe contact hole CH. The insulating portion 64 is composed of aninsulating material, such as a resin material, e.g., a polyimide. Asshown in FIG. 3, the recess 611 in the contact hole CH is filled withthe insulating portion 64. The insulating portion 64 is in contact withthe bottom and the inner periphery of the recess 611. Furthermore, theupper face of the insulating portion 64 protrudes from the surface ofthe first electrode 61. The insulating portion 64 also has the effect ofplanarizing bumps of the recess 611. From the standpoint of effectiveexpression of the effect, a resin material is particularly suitable asthe material for the insulating portion 64. When the resin material isused, first, the surface of the insulating portion 64 can be easilyplanarized by application of a liquid resin material at low cost;second, the insulating portion 64 having a sufficient thickness forplanarization of the recess 611 can be formed without the occurrence ofa crack; and third, the surface of the insulating portion 64 can beplanarized by melting the resin material resulting from heat treatmentfor curing the resin material.

Luminescent layers 66 shown in FIG. 1 are disposed the respective pixelsP and cover the surfaces of the first electrodes 61. As shown in FIG. 3,the luminescent layer 66 is not present in the region in which theinsulating portion 64 is disposed, i.e., the luminescent layer 66 isseparated by the insulating portion 64. Thus, the luminescent layer 66is not disposed in the space (recess 611) inside the contact hole CH.The luminescent layer 66 may be composed of any one of polymericmaterials and low molecular weight materials. Furthermore, to promotethe light emission from the luminescent layer 66 or to increase theluminous efficiency of the luminescent layer 66, a structure in whichvarious functional layers, such as a hole injection layer, a holetransport layer, an electron injection layer, an electron transportlayer, a hole blocking layer, and an electron blocking layer, arelaminated on the luminescent layer 66 may be used.

As shown in FIG. 3, the second electrode 62 shown in FIG. 1 serves as anelectrode covering the insulating portion 64 and the luminescent layer66. The second electrode 62 covers the entire surface of the substrate10. The second electrode 62 is continuously disposed over the pixels P.The second electrode 62 according to this embodiment is composed of anoptically transparent conductive material, such as ITO or IZO. Thus,light from the luminescent layer 66 toward a side opposite the substrate10 and light emitted from the luminescent layer 66 toward the substrate10 and then reflected from the surface of the reflective layer 44 emergefrom the viewing side through the second electrode 62. That is, theemissive device D according to this embodiment is of top emission typein which light emitted from the luminescent element E emerges from aside opposite the substrate 10. Furthermore, since the luminescent layer66 is not present in the region (contact hole CH) in which theinsulating portion 64 is disposed (and since the first electrode 61 isinsulated from the second electrode 62 by the insulating portion 64),this region does not contribute to light emission (dead space).

Most of optically transparent conductive materials have highresistivity; hence, the second electrode 62 composed of such a materialhas high resistance, thereby leading to significant voltage drop in theplane thereof. Therefore, potentials different in response to theposition in the plane of the second electrode 62 are applied to theluminescent elements E, thereby resulting in the nonuniformity of thequantity of light (nonuniformity of luminance and gray scale) in aluminescent region, in some cases.

To eliminate the nonuniformity of the quantity of light, in thisembodiment, the auxiliary lead 70 is disposed to support theconductivity of the second electrode 62. The auxiliary lead 70 iscomposed of a conductive material having a lower resistivity than thesecond electrode 62. The auxiliary lead 70 according to this embodimentis in contact with the surface of the second electrode 62 and iselectrically connected to the second electrode 62. According to thisstructure, most of current flows through the low-resistance auxiliarylead 70, thus suppressing the voltage drop in the second electrode 62.Therefore, a uniform potential is applied to the luminescent elements E,thus effectively suppressing the nonuniformity of the quantity of lightdue to the voltage drop. The auxiliary lead 70 according to thisembodiment is composed of an opaque conductive material. Morepreferably, the auxiliary lead 70 is composed of a material having lowerlight reflectivity than the drain electrode 34.

FIG. 4 is a plan view of an example of the structure of the auxiliarylead 70. FIG. 4 also shows outlines of the first electrodes 61 usingbroken lines. As shown in FIG. 4, the auxiliary lead 70 includes aplurality of first portions 71 extending in the X-direction in responseto the rows of the pixels P; and a plurality of second portions 72extending in the Y-direction in response to the columns of the pixels P,the first portions 71 crossing the second portions 72 to form a grid.However, the structure of the auxiliary lead 70 is not limited to theexample shown in FIG. 4. For example, a structure in which the auxiliarylead 70 only has the plurality of the first portions 71 extending in theX-direction may be used.

As shown in FIG. 2, the first portions 71 of the auxiliary lead 70overlap the contact holes CH of the second insulating layer 42 whenviewed in the direction perpendicular to the substrate 10. In moredetail, the first portions 71 according to this embodiment each have awidth substantially equal to or greater than the width (dimension in theY-direction) of the contact hole CH extending in the X-direction. Thus,as shown in FIGS. 2 and 3, each of the first portions 71 completelycovers a region (hereinafter, referred to as an “opening”) surrounded bythe inner periphery of the contact hole CH when viewed in the directionperpendicular to the substrate 10.

Most of conductive materials that can be used as the materials for thedrain electrode 34 of the driving transistor Tdr have lightreflectivity. Thus, in a known structure not having the auxiliary lead70, external light, such as sunlight or light from a luminaire, isincident to the viewing side, reaches the surface of the drain electrode34, and is then reflected from the surface to emerge from the viewingside, in some cases. The reflected light is referred to as “undesirablelight”. The undesired reflection has characteristics different fromthose of light from the luminescent layer 66, thus disadvantageouslycausing the nonuniformity of the quantity of light in the plane of theluminescent region. In contrast, in this embodiment, the opaqueauxiliary lead 70 completely covers the opening of the contact hole CH.Therefore, external light traveling from the viewing side to the drainelectrode 34 is blocked at the surface of the auxiliary lead 70, thesurface being adjacent to the viewing side. Even if external lightreaches the drain electrode 34, the undesirable reflection from thesurface is blocked at the surface of the auxiliary lead 70, the surfacebeing adjacent to the substrate 10. As described above, according tothis embodiment, the emergence of the undesirable reflection isprevented, thus uniformizing the quantity of light (luminance or grayscale) in the plane of the luminescent region.

In this embodiment, the structure in which the auxiliary lead 70 coversthe contact hole CH is exemplified. As a structure for expressing theeffect, for example, a structure in which an opaque component(hereinafter, referred to as a “light shield”) separate from theauxiliary lead 70 covers the contact hole CH is conceivable. In thisstructure, the auxiliary lead 70 does not overlap the contact hole CH(for example, see FIGS. 8 and 11). However, in this structure, regionsin which the contact hole CH and the auxiliary lead 70 are disposed donot contribute to light emission (dead space); hence, the aperture ratioof the emissive device D, i.e., the ratio of an area from which light isactually emitted to an area at which pixels P are disposed, isdisadvantageously limited. In contrast, in this embodiment, since theauxiliary lead 70 is also used as the light shield for the contact holeCH, it is possible to increase the aperture ratio, as compared with thestructures described above. In this embodiment, the increased apertureratio results in a reduction in electrical energy to be fed to theluminescent layer 66 for emitting light with a predetermined quantity oflight from the emissive device D. Higher electrical energy promotes thedegradation of characteristics of the luminescent layer 66. Therefore,in this embodiment, the increase in aperture ratio prolongs the life ofthe luminescent layer.

Furthermore, to surely connect the driving transistor Tdr with the firstelectrode 61, preferably, the area of the contact hole CH, i.e., thecontact area between the first electrode 61 and the drain electrode 34,is sufficiently ensured. However, in the structure in which theauxiliary lead 70 does not overlap the contact hole CH, an increase inthe area of the contact hole CH disadvantageously reduces the apertureratio by the increment. In contrast, in this embodiment, since theauxiliary lead 70 covers the contact hole CH, an increase in the area ofthe contact hole CH does not lead to a reduction in aperture ratiowithin the range of the region covered with the auxiliary lead 70. Thus,in this embodiment, as shown in FIG. 2, the contact hole CH that is longin the X-direction can sufficiently ensure the area of the contact holeCH, thereby reducing the resistance of the contact portion between thedriving transistor Tdr and the first electrode 61.

B: Second Embodiment

A second embodiment of the invention will be described below. Inemissive devices D having structures described below, the same orequivalent elements in the first embodiment are designated using thesame reference numerals, and redundant description is not repeated.

FIG. 5 is a plan view showing the structure of a pixel P according tothis embodiment. FIG. 6 is a cross-sectional view taken along line VI-VIin FIG. 5. In the first embodiment, the structure in which the auxiliarylead 70 completely covers the opening of the contact hole CH isexemplified. In contrast, in this embodiment, as shown in FIGS. 5 and 6,the auxiliary lead 70 (first portions 71) overlaps only a region A1 inthe opening of the contact hole CH. A region A2 in the opening shown inFIG. 6 is a region not overlapping the auxiliary lead 70.

As shown in FIG. 6, the emissive device D includes a substrate 80. Thesubstrate 80 is an optically transparent flat member to prevent theluminescent element E from coming into contact with air and water. Thesubstrate 80 faces the surface at which the luminescent element E isdisposed on the substrate 10. A light-shielding layer 81 is disposed atthe surface of the substrate 80 facing the substrate 10. Thelight-shielding, layer 81 is composed of an opaque material, such as ablack colored resin or a metal, e.g., chromium. As shown in FIGS. 5 and6, the light-shielding layer 81 includes a portion overlapping theregion A2 in the opening when viewed in the direction perpendicular tothe substrate 10. The light-shielding layer 81 according to thisembodiment is arranged in a grid in response to the pixels P similar tothe auxiliary lead 70 exemplified in FIG. 4 and completely covers theopening of the contact hole CH. Thus, the light-shielding, layer 81completely covers the auxiliary lead 70. Furthermore, thelight-shielding layer 81 according to this embodiment is composed of amaterial having lower light reflectivity than the drain electrode 34 andthe auxiliary lead 70.

In this structure, undesirable reflection reflected from the surface ofthe drain electrode 34 and then traveling in the region A2 is blocked bythe light-shielding layer 81. Thus, although the auxiliary lead 70 onlycovers the region A1, the same effect as that in the first embodiment issurely achieved.

Furthermore, in this embodiment, the light-shielding layer 81 composedof a material having a lower light reflectivity than the auxiliary lead70 overlaps the auxiliary lead 70. In this structure, external lighttraveling from the viewing side to the auxiliary lead 70 is blocked bythe light-shielding layer 81. Furthermore, even if external lightreaches the auxiliary lead 70, reflection from the surface is blocked bythe light-shielding layer 81. Thus, even when the auxiliary lead 70 iscomposed of a material having a high light reflectivity, thenonuniformity of the quantity of light due to the reflection from theauxiliary lead 70 is suppressed. That is, according to this embodiment,it is possible to prevent the emergence of the reflection (undesirablereflection) from the drain electrode 34 and the auxiliary lead 70 to theviewing side.

C: Third Embodiment

FIG. 7 is a plan view of the structure of a pixel P according to a thirdembodiment of the invention. FIG. 8 is a cross-sectional view takenalong line VIII-VIII in FIG. 7. In each of the first and secondembodiments, the structure in which the auxiliary lead 70 overlaps thecontact hole CH when viewed in the direction perpendicular to thesubstrate 10 is exemplified. In contrast, as shown in FIGS. 7 and 8, theauxiliary lead 70 according to this embodiment does not overlap theopening.

As shown in FIG. 8, the insulating portion 64 according to thisembodiment extends from the inside the contact hole CH toward thenegative direction of the Y-direction and overlaps the periphery of thefirst electrode 61 of the subsequent pixel P disposed in the negativedirection of the Y-direction. A portion 641 of the insulating portion 64not overlapping the contact hole CH, i.e., a portion is in the negativedirection of the Y-direction with respect to the contact hole CH, isdisposed on the second insulating layer 42; hence, the portion 641 isflat compared with the portion of the insulating portion 64 overlappingthe contact hole CH. As shown in FIGS. 7 and 8, the auxiliary lead 70 isdisposed on the surface (flat surface) of the portion 641. The secondelectrode 62 covers the auxiliary lead 70.

In this embodiment, similarly to the second embodiment, thelight-shielding layer 81 is disposed on the substrate 80. Thelight-shielding layer 81 is composed of an opaque material having alower light reflectivity than the drain electrode 34 and the auxiliarylead 70. As shown in FIGS. 7 and 8, the light-shielding layer 81 coversboth the contact hole CH and the auxiliary lead 70 when viewed in thedirection perpendicular to the substrate 10. Thus, also in thisembodiment, the same effect as that in the first and second embodimentsis achieved.

In some cases, bumps in response to the shape (recess) of the contacthole CH are generated on the surfaces of- the elements (insulatingportion 64 and second electrode 62) covering the contact hole CH. Thus,in a structure in which the auxiliary lead 70 is disposed on theelements, the auxiliary lead 70 may be broken or detached due to thebumps on the surface. In contrast, in this embodiment, the auxiliarylead 70 is disposed on the surface of the flat portion 641 of theinsulating portion 64, the flat portion 641 being remote from thecontact hole CH. Therefore, it is possible to effectively prevent thebreakage and detachment of the auxiliary lead 70.

D: Fourth Embodiment

FIG. 9 is a cross-sectional view showing the structure of a pixel Paccording to a fourth embodiment of the invention. The pixel P accordingto this embodiment is the same planar structure as that in FIG. 2. Thatis, FIG. 9 corresponds to a cross-sectional view taken along lineIII-III in FIG. 2.

As shown in FIG. 9, in the emissive device D according to thisembodiment, the insulating portion 641 with which the contact hole CH isfilled is not disposed. The luminescent layer 66 is disposed across thesubstrate 10 so as to continuously extend over the plurality of thepixels P. The first electrodes 61 are disposed the respective pixels P,the first electrodes 61 being separated each other. Thus, although theluminescent layer 66 extends over the plurality of the pixels P, thequantity of light of the luminescent layer 66 is controlled for everypixel P similar to the above-described embodiments.

In the structure in which each individual luminescent layer 66 isseparated for every pixel P as in the first to third embodiments, it ispossible to change an emission color from each pixel P by appropriatelyselecting the material of the luminescent layer 66. However, in astructure in which the luminescent layer 66 extends over the pluralityof the pixels P as in this embodiment, the emission color from theluminescent layer 66 cannot be changed for every pixel P. Thus, torealize an image display including a plurality of colors in thestructure according to this embodiment, for example, a color filter inresponse to the pixels P is preferably disposed on the substrate 80 (notshown in FIG. 9).

As shown in FIG. 9, the portion of the luminescent layer 66 covering thecontact hole CH is disposed inside the recess 611l of the firstelectrode 61 (space in the contact hole CH) and is in contact with theinner periphery and the bottom of the recess 611. The luminescent layer66 has a sufficiently thinner thickness compared with the externaldimension of the contact hole CH, thereby forming a recess (depression)of the luminescent layer 66 in response to the bump of the recess 611 ofthe first electrode 61.

The auxiliary lead 70 (in more detail, the first portions 71) isdisposed on the surface of the second electrode 62 so as to completelycover the opening of the contact hole CH when viewed in the directionperpendicular to the substrate 10), as in the first embodiment. Thus,also in this embodiment, the same effect as that in the first embodimentis achieved. In this embodiment, it is possible to simultaneously fromthe luminescent layers 66 of pixels P in a single step. Furthermore,there is no need to form the insulating portion 64 as in the first tothird embodiments. Therefore, it is possible to simplify a productionprocess and reduce production costs, as compared with theabove-described embodiments.

As shown in FIG. 9, a portion 661 of the luminescent layer 66 coveringthe inner periphery of the recess 611 of the first electrode 61 isdisposed between the first electrode 61 and the second electrode 62, inthe same way as other portions. Therefore, light (undesirable light) isalso emitted from the portion 661 in operation of the luminescentelement E. The undesirable light has characteristics, such as thequantity of light and spectral characteristics, different from those ofthe light emitted from other portions. Thus, when the undesirable lightemerges from the viewing side, the uniformity of light emission of theemissive device D is degraded. Furthermore, light emitted from theportions of the luminescent layer 66 other than the portion 661 andlight emitted from the portion 661 interfere with each other. As aresult, a specific colored light can emerge from the viewing side. Inthis embodiment, since the auxiliary lead 70 covers the contact hole CH,undesirable light traveling from the recess 611 toward the viewing sideis blocked by the auxiliary lead 70. As described above, in thisembodiment, it is possible to block both the undesirable reflection andthe undesirable light to uniformize the quantity of light in theluminescent region.

E: Fifth Embodiment

FIG. 10 is a cross-sectional view showing the structure of a pixel Paccording to a fifth embodiment of the invention. The pixel P accordingto this embodiment has the same planar structure as that in FIG. 5. Theluminescent layer 66 according to this embodiment extends over theplurality of the pixels P and is disposed in the space inside thecontact hole CH, as in the fourth embodiment (FIG. 9). The auxiliarylead 70 overlaps only the region A1 of the opening, and thelight-shielding layer 81 completely covers the opening (region A1 andregion A2) and is disposed on a surface of the substrate 80, as in thesecond embodiment (FIGS. 5 and 6). Thus, according to this embodiment,the same effect as in the second and fourth embodiments is achieved.

As described above, in the structure in which the light-shielding layer81 is disposed at the viewing side with respect to the auxiliary lead70, it is possible to reduce the influence of external light reflectedfrom the surface of the auxiliary lead 70. In the structure in which theluminescent layer 66 is disposed inside the contact hole CH as in eachof the fourth and fifth embodiments, for example, the undesirable lightfrom the portion 661 is repeatedly reflected between the back surface ofthe auxiliary lead 70 (the surface adjacent to the substrate 10) and adrain electrode 342 or the reflective layer 44 to possibly emerge fromthe viewing side, in the end. From the standpoint of the prevention ofthe emergence of the undesirable light, a structure in which a lightshield having a lower light reflectivity than the auxiliary lead 70, inother words, the structure in which the light shield having a higherlight absorbance than the auxiliary lead 70, is disposed between theauxiliary lead 70 and the luminescent layer 66 (for example, between theauxiliary lead 70 and the second electrode 62 in FIGS. 9 and 10) ispreferably used. In this structure, undesirable light emitted from theportion 661 of the luminescent layer 66 does not reach the back surfaceof the auxiliary lead 70; hence, it is possible to surely prevent thenonuniformity of the light emission due to the undesirable lightreflected from the auxiliary lead 70.

F: Sixth Embodiment

FIG. 11 is a cross-sectional view showing the structure of a pixel Paccording to a sixth embodiment of the invention. The pixel P accordingto this embodiment has the same planar structure as that in FIG. 7. Theluminescent layer 66 according to this embodiment extends over theplurality of the pixels P and is disposed in the space inside thecontact hole CH, as in the fourth embodiment (FIG. 9). The auxiliarylead 70 is disposed on the surface (flat surface) of the portion of theluminescent layer 66 not overlapping the contact hole CH, and thelight-shielding layer 81 is disposed on a surface of the substrate 80 soas to overlap both the contact hole CH and the auxiliary lead 70, as inthe third embodiment (FIGS. 7 and 8). Thus, according to thisembodiment, the same effect as in the third and fourth embodiments isachieved.

G: Seventh Embodiment

FIG. 12 is a plan view showing the structure of a pixel P according to aseventh embodiment of the invention. FIG. 13 is a cross-sectional viewtaken along line XIII-XIII in FIG. 12. As shown in FIGS. 12 and 13, thestructure of the elements disposed on the substrate 10 is identical tothe sixth embodiment (FIG. 11). The light-shielding layer 81 accordingto this embodiment covers a region A3, which is part of the opening, andthe auxiliary lead 70 but does not cover a region A4, which is a regionof the opening other than the region A3.

As shown in FIG. 13, light emitted from the portion of the luminescentlayer 66 overlapping the contact hole CH (in particular, a portioncovering the bottom of the recess 611) partially emerges from theviewing side through the region A4 as indicated by Arrow L in FIG. 13.Therefore, according to this embodiment, the region A4 contributes to anincrease in aperture ratio, as compared with the structure in the sixthembodiment.

H: Eighth Embodiment

FIG. 14 is a plan view showing the structure of a pixel P according toan eighth embodiment of the invention. FIG. 15 is a cross-sectional viewtaken along line XV-XV in FIG. 14. In the above-described embodiments,top-emission-type emissive device D is exemplified. In contrast, theemissive device D according to this embodiment is of a bottom emissiontype. That is, as shown in FIG. 15, the reflective layer 44 describedabove is not disposed. The second electrode 62 is composed of a lightreflective conductive material in place of the reflective layer 44.Thus, light emitted from the luminescent layer 66 toward the substrate10 and light emitted from the luminescent layer 66 toward a sideopposite the substrate 10 and then reflected from the surface of thesecond electrode 62 pass though the first electrode 61 and the substrate10 to emerge downward in FIG. 15.

Also in this embodiment, the auxiliary lead 70 is used as a light shieldfor preventing the emergence of reflection from the drain electrode 34,as in the first and second embodiments. In this embodiment, thesubstrate 10 side (lower side in FIG. 15) is the viewing side withrespect to the luminescent layer 66. As shown in FIG. 15, the auxiliarylead 70 is disposed between the drain electrode 34 and the substrate 10.The auxiliary lead 70 according to this embodiment and the gateelectrode 242 (furthermore, the selection lines 11 and the intersectionportion 131) is simultaneously formed by patterning a single conductivefilm entirely disposed on the substrate 10. Thus, the auxiliary lead 70is composed of the same material as that of the gate electrode 242.

The auxiliary lead 70 overlaps the drain electrode 34 (in more detail,the opening of the contact hole CH) when viewed in the directionperpendicular to the substrate 10 like FIG. 14. As shown in FIG. 14, thesecond electrode 62 is electrically connected to the auxiliary lead 70via a contact hole CH5 passing through the first insulating layer 41 andthe second insulating layer 42. Also according to this structure, thesame effect as that in the first and second embodiments is achieved. Forexample, in this embodiment, external light emitted from the viewingside (lower side in FIG. 15) toward the drain electrode 34 andundesirable light reflected from the surface of the drain electrode 34toward the viewing side are blocked by the auxiliary lead 70, therebyuniformizing the quantity of light in the plane in the luminescentregion.

The auxiliary lead 703 according to this embodiment is formed by thesame process as that for forming the gate electrode 242 (furthermore,selection lines 11 and the intersection portion 131). In this structure,there is no need for the formation and patterning of a conductive filmused for only forming the auxiliary lead 70. Therefore, it is possibleto simplify the production process and reduce production costs, ascompared with the case where the auxiliary lead 70 is formed by aprocess separate from a process for forming another element.Furthermore, in this embodiment, there in no need for the formation ofthe auxiliary lead 70 on the surface of the luminescent layer 66 and theinsulating portion 64, the luminescent layer 66 and the insulatingportion 64 being composed of organic materials. Moreover, the auxiliarylead 70 is composed of a low-resistance conductive material common tothe gate electrode 242. Thus, advantageously, the resistance of theauxiliary lead 70 is easily reduced, as compared with the case where theauxiliary lead 70 is disposed on surfaces of the luminescent layer 66and the insulating portion 64.

As described above, the bottom-emission-type emissive device D isexemplified. In this embodiment, the emissive device D may be of a topemission type. In the top-emission-type emissive device D, thereflective layer 44 is disposed between the first electrode 61 and thesubstrate 10. The second electrode 62 is composed of an opticallytransparent material. According to this structure, an increase in thearea of the contact hole CH does not lead to a reduction in apertureratio within the range of the region covered with the auxiliary lead 70,as in the first embodiment. Thus, it is possible to sufficiently ensurethe area of the contact hole CH and to reduce the resistance of thecontact area between the driving transistor Tdr and the first electrode61. Furthermore, in the top-emission-type emissive device D in which theauxiliary lead 70 is disposed under the first electrode 61 as shown inFIGS. 14 and 15, even when the auxiliary lead 70 is composed of anopaque material, light emitted from the luminescent layer 66 does notblocked by the auxiliary lead 70. Therefore, it is possible toadvantageously increase the aperture ratio.

I: Ninth Embodiment

In each of the above-described embodiments, the auxiliary lead 70 (FIG.4) arranged in a grid in response to the rows and columns of the pixelsP is exemplified. The structure of the auxiliary lead 70 may beappropriately changed. In this embodiment, one auxiliary lead 70 isdisposed with respect to a plurality of rows or a plurality of columns.

FIG. 16 is a plan view showing the arrangement of a plurality ofluminescent elements E according to a ninth embodiment of the invention.FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. 16.In FIGS. 16 and 17, the elements, such as the selection transistor Tsland the capacitor C, are appropriately omitted.

Similarly to each of the above-described embodiments, the firstelectrodes 61 each having a substantially rectangular shape and eachhaving a length in the Y-direction are arrayed in a matrix of theX-direction and the Y-direction on the surface of the second insulatinglayer 42. In this structure, the reflective layer 44 described in eachof the above-described embodiments is omitted.

The insulating portion 64 is disposed on the surface of the firstelectrode 61 on the second insulating layer 42. As shown in FIGS. 16 and17, an opening 641 (hole passing through the insulating portion 64 alongthe thickness) is disposed in each of the regions of the insulatingportion 64 overlapping the first electrode 61. As shown in FIG. 16, theentire inner periphery of the opening 641 is located inwardly comparedwith the perimeter of the first electrode 61, when viewed in thedirection perpendicular to the substrate 10. As described above, infact, the perimeter of the first electrode 61 is covered with theinsulating portion 64. However, in FIG. 16, for the sake of convenience,the contour of the first electrode 61 is illustrated using a solid line.

As shown in FIG. 17, the luminescent layer 66 is continuously disposedover the plurality of the luminescent elements E so as to completelycover the surface of the second insulating layer 42 having theinsulating portion 64. That is, the luminescent layer 66 includes aportion (luminescent portion) disposed in the opening 641 and oppositethe first electrode 61; and a portion disposed on the surface of theinsulating portion 64.

As shown in FIG. 17, the second electrode 61 is a conductive filmcontinuously formed over the plurality of the luminescent elements E,the second electrode 62 covering the luminescent layer 66 and theinsulating portion 64. That is, the second electrode 62 includes aportion disposed in the opening 641 and opposite the first electrode 61provided with the luminescent layer 66 therebetween; and a portiondisposed on the insulating portion 64. As shown in FIGS. 16 and 17, in alaminate having the first electrode 61, the luminescent layer 66, andthe second electrode 62, a portion disposed inside the inner peripheryof the opening 641, in other words, a region in which a current flowsfrom the first electrode 61 to the second electrode 62 is defined as theluminescent element E, when viewed in the direction perpendicular to thesubstrate 10. A region of the luminescent layer 66 overlapping theinsulating portion 64 does not illuminate because a current is blockedby the insulating portion 64l disposed between the first electrode 61and the second electrode 62. That is, the insulating portions 64 defineoutlines of the luminescent elements E.

As shown in FIGS. 16 and 17, the plurality of auxiliary leads 70extending in the X-direction are each disposed between the insulatingportion 64 (luminescent layer 66) and the second electrode 62. Aspecific structure of each auxiliary lead 70 according to thisembodiment is described below. Three rows of the luminescent elements E,i.e., row i to row (i+3) of the luminescent elements E are shown in FIG.16. Row i and row (i+2) are defined as even rows. Row (i+1) and row(i+3) are defined as odd rows.

As shown in FIG. 16, each auxiliary lead 70 is disposed at space S1between the luminescent elements E of an even row and the luminescentelements E of an odd row adjacent to the even row in the positivedirection of the Y-direction (for example, space S1 between row i androw (i+1) and space S1 between row (i+2) and row (i+3)). On the otherhand, none of the auxiliary leads 70 is disposed at space 82 between theluminescent elements E of an odd row and the luminescent elements E ofan even row adjacent to the odd row in the positive direction of theY-direction. That is, when two rows of an odd row and an even rowadjacent to the odd row in the positive direction of the Y-direction aredefined as a unit, each auxiliary lead 70 is disposed at space S1, whichis a space between adjacent units in the Y-direction. None of theauxiliary leads 70 is disposed at space 82, which is a space betweenadjacent rows defining the unit. Consequently, in this embodiment, oneauxiliary lead 70 is disposed with respect to a plurality of rows (forevery two rows).

The contact hole CH for connecting the first electrode 61 with thedriving transistor Tdr of each luminescent element E is disposedadjacent to the auxiliary lead 70 with respect to the luminescentelement E. Thus, the position of the contact hole CH in the Y-directionin each luminescent element E of an odd row is opposite the position ofthe contact hole CH in each luminescent element E of an even row. Thatis, in an even row, the contact hole CH is disposed at a positive sideof each luminescent element E in the Y-direction. In contrast, in an oddrow, the contact hole CH is disposed at a negative side of eachluminescent element E in the Y-direction.

As shown in FIGS. 16 and 17, the auxiliary leads 70 each has a widthsubstantially identical to the width of the insulating portion 64 tocover space S1 between the luminescent elements E and to cover thecontact holes CH as in the first and second embodiments. That is, theauxiliary leads 70 each cover the contact hole CH of each luminescentelement E of an even row and the contact hole CH of each luminescentelement E of an odd row adjacent to the even row in the positivedirection of the Y-direction. In other words, one edge of each auxiliarylead 70 in the width direction (the upper end portion in FIG. 16) islocated at a space between each luminescent element E of an even row andthe corresponding contact hole CH. The other edge is located at a spacebetween each luminescent element E of an odd row and the correspondingcontact hole CH.

Each auxiliary lead 70 deviates from a design position for reasons ofproduction techniques, in some cases. When the auxiliary lead 70 isformed by evaporation with a mask (described in detail below), theauxiliary lead 70 is formed at a position different from a predeterminedposition (design position), in some cases, because of the dimensionerror of the mask and the positional error between the substrate 10 andthe mask. Even if the auxiliary lead 70 has a positional error, a gap(hereinafter, referred to as a “margin region”) is ensured between thedesign position of the auxiliary lead 70 and each luminescent element Eadjacent to the auxiliary lead 70 in the width direction such that theauxiliary lead 70 does not overlap the luminescent element E when viewedin the direction perpendicular to the substrate 10 (that is, theaperture ratio is not reduced).

As described above, in this embodiment, since one auxiliary lead 70 isdisposed for every two rows, the total area of a region at which theauxiliary leads 70 are disposed and the margin region in the luminescentregion is reduced, as compared with the structure in which the auxiliaryleads 70 are disposed at all spaces between adjacent rows and betweenadjacent columns (for example, the structure shown in FIG. 4;hereinafter, the structure being referred to as a “comparativestructure”) as in the first embodiment. Thus, advantageously, thestructure according to this embodiment easily achieves a balance betweenthe maintenance of the aperture ratio and a reduction in the resistanceof the auxiliary lead 70. That is, for example, in the case where theaperture ratio is maintained at a level equal to that of the comparativestructure, each auxiliary lead 70 surely has a greater line widthcompared with the comparative structure because the number of theauxiliary leads 70 and tile areas of the margin regions are reduced;hence, the resistance of each auxiliary lead 70 can be reduced.Furthermore, in this embodiment, many contact holes CH are denselyarranged in the space between the sequence of the luminescent elements Eof an even row and the sequence of the luminescent elements E of an oddrow adjacent to the even row in the positive direction of theY-direction. Thus, an increase in the line width of each auxiliary lead70 can easily cover the contact holes CH with the correspondingauxiliary lead 70. On the other hand, in the case where the line widthof each auxiliary lead 70 is maintained at a level equal to that of thecomparative structure, the area of each luminescent element E is surelyincreased because of the reduced areas of the auxiliary leads 70 and themargin regions in the luminescent region. Therefore, the structureaccording to this embodiment can have a greater aperture ratio than thecomparative structure. Furthermore, the increased aperture ratio resultsin a reduction in electrical energy (current) to be fed to theluminescent elements E for emitting light with a predetermined quantityof light from the luminescent region. Therefore, the life of theluminescent elements E can be advantageously prolonged by suppressingdegradation due to the feed of the electrical energy.

In a process for producing the emissive device D according to theembodiment, a step of forming the auxiliary leads 70 will be describedbelow. The auxiliary leads 70 according to the embodiment are formed byevaporation (vacuum evaporation) using a mask. Elements other than theauxiliary leads 70 are formed by known techniques.

FIG. 18 is a cross-sectional view illustrating a step of forming theauxiliary leads 70 (corresponding to FIG. 17). As shown in FIG. 18, amask 75 for use in evaporation is prepared before the formation of theauxiliary leads 70. The mask 75 has an opening at a region RA and anunperforated region RB other than the region RA. The region RA is in theform of a slit extending in the X-direction, the slit facing a regionfor forming each auxiliary lead 70. The region RA faces the space S1between an even row (row i or row (i+2)) and an odd row adjacent to theeven row (row (i+1) or row (i+3)) in the positive direction of theY-direction (to be more exact, a region obtained by the elimination ofthe margin regions from space S1). On the other hand, the region RBincludes a subregion RB1 and a subregion RB2. The subregion RB1 facesthe luminescent elements E. The subregion RB2 faces space 82 between anodd row (row (i+1)) and an even row (row (i+2)) adjacent to the odd rowin the positive direction of the Y-direction.

The auxiliary leads 70 are formed by evaporation using the mask 75. Asshown in FIG. 18, an emissive device D having the luminescent layer 66(before forming the second electrode 62) is placed in vacuum. The mask75 is placed so as to face the luminescent layer 66. The vapor V of amaterial having a lower resistivity than the second electrode 62 isselectively deposited on the surface of the luminescent layer 66 to formthe auxiliary leads 70 having the shape shown in FIG. 16.

In the emissive device D according to the embodiment, one auxiliary lead70 is disposed for every two rows of the luminescent elements E. Thus,as shown in FIG. 18, there is no need for perforating the region RB2 ofthe mask 75. That is, it is possible to maintain the mechanical strengthof the mask 75, as compared with the case where the auxiliary leads 70are disposed at all spaces between adjacent rows like the comparativestructure (the case where openings each having the same width dimensionas the region RA are also formed in the region RB2 of the mask 75).Therefore, it is possible to effectively prevent the error and failureof the auxiliary leads 70 due to the deformation of the mask 75 (forexample, deformation due to its own weight). Furthermore, since theerror of the auxiliary leads 70 is reduced, each auxiliary lead 70 caneasily cover the contact holes CH with high precision.

In FIG. 16, the structure in which each auxiliary lead 70 extends alongthe short side of each luminescent element E (X-direction) isexemplified. As shown in FIG. 19, a structure in which each auxiliarylead 70 extends along the long side of each luminescent element E(Y-direction) may be used. Three columns of the luminescent elements E,i.e., column j to column (j+3) of the luminescent elements E are shownin FIG. 19. Column j and column (j+2) are defined as even columns.Column (j+1) and column (j+3) are defined as odd column.

As shown in FIG. 19, in this embodiment, one auxiliary lead 70 isdisposed with respect to a plurality of columns (for every two columns).That is, each auxiliary lead 70 extending in the Y-direction is disposedat space S1 between column j and column (j+1) and space S1 betweencolumn (j+2) and column (j+3), whereas none of the auxiliary leads 70 isdisposed at space S2 between column (j+1) and column (j+2). Furthermore,each auxiliary lead 70 covers contact holes CH of the luminescentelements E disposed at both sides of the auxiliary lead 70. Also in thestructure shown in FIG. 19, the same effect as that of the structureshown in FIG. 16 is achieved.

The resistance of a current path from each luminescent element E to thecorresponding auxiliary lead 70 (hereinafter, the resistance beingreferred to as a “cathode resistance”) is inversely proportional to thedimension W of each luminescent element E in the direction to which eachauxiliary lead 70 extends (see FIGS. 16 and 19). In the structure shownin FIG. 19, since the auxiliary leads 70 each extend along the long sideof each luminescent element E, the dimension W can be increased, ascompared with the structure in which the auxiliary leads 70 each extendalong the short side of each luminescent element E shown in FIG. 16.Thus, the structure shown in FIG. 19 reduces the cathode resistancecompared with that in the structure shown in FIG. 16. This suppressesthe voltage drop across the second electrode 62; hence, the power-supplypotential Vdd required for driving the luminescent elements E can bereduced compared with the case of high cathode resistance.

J: Modification

Various modifications of the above-described embodiments may be made.Specific modifications will be exemplified as follows. The modificationsmay be in combination.

(1) In the above-described embodiments, the structure in which thelight-shielding layer 81 is disposed on the substrate 80 is exemplified.The position of the light-shielding layer 81 may be appropriatelychanged. For example, a structure in which the light-shielding layer 81is disposed on the surface of the second electrode 62 may be used.Furthermore, in the structure in which the auxiliary lead 70 is disposedon the surface of the second electrode 62 (for example, the first,second, fourth, and fifth embodiments), the light-shielding layer 81 maybe disposed on the surface of the auxiliary lead 70.

(2) In each of the second embodiment (FIGS. 5 and 6) and the fifthembodiment (FIG. 10), the structure in which the light-shielding layer81 covers the region A2, not covered with the auxiliary lead 70, of theopening of the contact hole CH is exemplified. The light-shielding layer81 may be omitted, if necessary. In such a structure not including thelight-shielding layer 81, undesirable reflection from the region A2emerges from the viewing side. In the fifth embodiment, undesirablelight also emerges from the viewing side. However, since undesirablereflection and undesirable light from the region A1 are blocked by theauxiliary lead 70, the intended effect of suppressing the nonuniformityof quantity of light in the luminescent region is surely achieved, ascompared with a known structure in which none of the light shieldscovers the contact hole CH.

In each of the first embodiment (FIGS. 2 and 3) and the fourthembodiment (FIG. 9), the structure in which the auxiliary lead 70completely covers the opening of the contact hole CH is exemplified. Tofurther surely prevent undesirable reflection and undesirable light, thelight-shielding layer S1 including a portion overlapping the contacthole CH may be disposed. Furthermore, in the structure in which thelight-shielding layer 81 at least partially overlaps the contact hole CH(for example, the second, third, fifth, sixth, and seventh embodiments),if the voltage drop due to the second electrode 62 does not causeproblems, the auxiliary lead 70 may be omitted, according to need.

As described above, in the invention, a structure in which an opaquecomponent (light shield) is disposed so as to overlap the contact holeCH when viewed in the direction perpendicular to the substrate 10 isneeded, regardless of the structure of the light shield (auxiliary lead70 or light-shielding layer 81) and the material (conductive,insulative, or the like). From the standpoint of the sure prevention ofthe nonuniformity of the quantity of light due to the contact hole CH, astructure in which the light shield extends over a range greater thanthe contact hole CH is preferred.

(3) In each of the first to third embodiments, the structure in whichthe insulating portion 64 does not overlap the luminescent layer 66 isexemplified. As shown in FIG. 20, a structure in which the luminescentlayer 66 covers the insulating portion 64 may be used. According to thisstructure, the luminescent layer 66 and the second electrode 62 aredisposed on the fiat surface of the insulating portion 64 with which thecontact hole CH is filled. Thus, it is possible to prevent the failureand break of the luminescent layer 66 and the second electrode 62 due tobumps of the contact hole CH. Furthermore, the luminescent layer 66 isnot disposed inside the recess 611 as in the first to third embodiments.Thus, the portion of the luminescent layer 66 covering the contact holeCH is remote from the first electrode 61 provided with the insulatingportion 64 therebetween (that is, a current does not flow). Therefore,according to the structure shown in FIG. 20, it is possible to preventthe generation of the undesirable light which causes problems in eachstructure shown in FIGS. 9 to 13.

(4) In the eighth embodiment, the structure in which the auxiliary lead70 is used to block undesirable reflection from the drain electrode 34is exemplified. An element other than the auxiliary lead 70 may be usedto block the undesirable reflection. For example, a structure in whichan opaque film separate from the auxiliary lead 70 is disposed betweenthe drain electrode 34 and the substrate 10 may be used. The auxiliarylead 70 in this structure may be disposed on the surface of the secondelectrode 62, as in the first embodiment.

(5) The above-described structure may be in combination, according toneed. For example, in the third embodiment (FIGS. 7 and 8), a structurein which the light-shielding layer 81 is disposed so as not to overlapthe region A4 of the opening of the contact hole CH may be used, as inthe seventh embodiment (FIGS. 12 and 13).

(6) In each of the above-described embodiments, the structure in whichthe luminescent layer 66 is composed of an organic electroluminescentmaterial is exemplified. The material of the luminescent layer 66 may beappropriately changed. For example, the luminescent layer may becomposed of an inorganic electroluminescent material. The luminescentlayer according to an aspect of the invention is required to be composedof a luminescent material that illuminates using electrical energy.

K: Applications

An electronic apparatus including an emissive device according to anaspect of the invention will be described below. FIG. 21 is aperspective view of a mobile personal computer including the emissivedevice D, which serves as a display device, according to any one of theembodiments. A personal computer 2,000 includes the emissive device Dserving as the display device and a main body 2,010. The main body 2,010includes a power switch 2,001 and a keyboard 2,002. The emissive deviceID includes a luminescent element E composed of an organicelectroluminescent material and thus has an easily viewable screen witha wide viewing angle.

FIG. 22 shows a cellular phone including the emissive device D accordingto any one of the embodiments. A cellular phone 3,000 includes aplurality of operation buttons 3,001, a plurality of scroll buttons3,002 and an emissive device D serving as a display. The scroll buttons3,002 are operated to scroll an image on the screen.

FIG. 23 shows a personal digital assistant (PDA) including the emissivedevice ID according to any one of the embodiments. A personal digitalassistant 4,000 includes a plurality of operation buttons 4,001, a powerswitch 4,002, and the emissive device D serving as a display. Turningthe power switch 4,002 on displays information, such as an addresslisting or a schedule book, on the emissive device D.

Examples of the electronic apparatus to which the emissive deviceaccording to an aspect of the invention is applied include digital stillcameras, television sets, video cameras, car navigation systems, pagers,electronic notebooks, electronic paper, calculators, word processors,workstations, videophones, point-of-sale terminals, printers, scanners,copying machines, video players, and apparatuses with touch panels, inaddition to apparatuses indicated in FIGS. 21 to 23. Furthermore,applications of the emissive device according to an aspect of theinvention are not limited to displaying images. For example, inimage-forming apparatuses, such as optical writing printers andelectronic copying machines, writing heads for exposing photoreceptorsin response to images to be formed on recording materials, such asprinting paper, are used. The emissive device according to an aspect ofthe invention may be used as the writing head.

1. An emissive device, comprising: a substrate; a switching element overthe substrate; an insulating layer covering the switching element, theinsulating layer defining a contact hole; a first electrode over theinsulating layer and electrically coupled to the switching element viathe contact hole; a second electrode spaced from the first electrode; aluminescent layer disposed between the first electrode and thesecondelectrode, the luminescent layer emitting light from a lightemitting side of the device; and a light shield disposed at the lightemitting side of the device, the light shield having a portion coveringthe contact hole so as to intersect an axis of the contact hole.
 2. Theemissive device according to claim 1, the switching element furtherincluding: a switching element electrode extending through the contacthole and having a portion not covered with the insulating layer, theportion being in contact with the first electrode; and the light shieldbeing composed of a material having a lower light reflectivity than alight reflectivity of the switching element electrode.
 3. The emissivedevice according to claim 1, the light shield being an auxiliary leadcomposed of a conductive material having a lower resistivity than thesecond electrode, the light shield being electrically coupled to thesecond electrode.
 4. The emissive device according to claim 3, an innerperiphery of the contact hole defining a contact hole region extendingin a direction perpendicular to an axial direction of the contact hole,the auxiliary lead completely covering the contact hole region relativeto the axial direction of the contact hole.
 5. The emissive deviceaccording to claim 3, an inner periphery of the contact hole defining acontact hole region extending in a direction perpendicular to an axialdirection of the contact hole, the auxiliary lead partially overlappingthe contact hole region relative to the axial direction of the contacthole, the emissive device further comprising: a light-shielding layerhaving a portion overlapping a region that does not overlap theauxiliary lead in the contact hole region.
 6. The emissive deviceaccording to claim 1, further comprising: an auxiliary lead composed ofa conductive material having a lower resistivity than a resistivity ofthe second electrode, the auxiliary lead being electrically coupled tothe second electrode, the light shield overlapping the auxiliary leadrelative to an axial direction of the contact hole.
 7. The emissivedevice according to claim 3, further comprising: a plurality ofluminescent elements, each of the luminescent elements including thefirst electrode, the second electrode, and the luminescent layer; aplurality of element groups, each of the element groups including atleast one of the luminescent elements arranged in a firstdirection andat least two of the luminescent elements arranged in a second directionthat intersects the first direction, the plurality of the element groupsbeing arranged in the second direction, the auxiliary lead beingdisposed in a space between a first element group and a second elementgroup that is adjacent to the first elementgroup in the seconddirection, the auxiliary lead extending in the first direction, theauxiliary lead not being disposed in a space between the at least twoluminescent elements of each element group arranged in the seconddirection.
 8. The emissive device according to claim 1, furthercomprising: an insulating portion composed of an insulating material,the insulating portion filling at least a portion of the contact hole;the luminescent layer being spaced from the contact hole.
 9. Theemissive device according to claim 1, the light shield extending in apredetermineddirection that is perpendicular to an axial direction ofthe contact hole; and the contact hole extending along the predetermineddirection.
 10. The emissive device according to claim 1, the firstelectrode transmitting light from the luminescent layer; the switchingelement further including: a switching element electrode extendingthrough the contact hole and having a portion not covered with theinsulating layer, the portion being in contact with the first electrode;and the light shield being composed of a material having a lower lightreflectivity than a light reflectivity of the switching elementelectrode, being disposed between the switching element electrode andthe substrate, and being opposite to the electrode.
 11. The emissivedevice according to claim 10, further comprising: an auxiliary leadcomposed of a conductive material having a lower resistivity than aresistivity of the second electrode, the auxiliary lead beingelectrically coupled to the second electrode via the contact hole, thelight shield being the auxiliary lead.
 12. The emissive device accordingtoclaim 10, the switching element further including: a plurality ofelectrodes; and the light shield being composed of the same material asany one of the plurality of the electrodes.
 13. An electronic apparatus,comprising: the emissive device according to claim
 1. 14. An emissivedevice, comprising: a switching element; an insulating layer over atleast a portion of the switching element, the insulating layer defininga contact hole directly over a portion of the switching element; a firstelectrode over at least a portion of the insulating layer, a portion ofthe first electrode extending into the contact hole so as to beelectrically coupled with the switching element; a luminescent layer onat least a portion of the first electrode; a second electrode on theluminescent layer; and a light shield directly over the contact hole soas to reduce nonuniformity of viewable light due to the contact hole.15. The emissive device according to claim 14, the luminescent layer notextending directly over the contact hole.
 16. The missive deviceaccording to claim 14, the luminescent layer extending directly over thecontact hole.